War!

"Oh, I remember -- the time the Church tried her
strength against us the first time, and presently thought
it wise to wait for a hopefuler season. Well, how have
you arranged the fence?"

"I start twelve immensely strong wires -- naked, not
insulated -- from a big dynamo in the cave -- dynamo
with no brushes except a positive and a negative one --"

"Yes, that's right."

"The wires go out from the cave and fence in a
circle of level ground a hundred yards in diameter;
they make twelve independent fences, ten feet apart --
that is to say, twelve circles within circles -- and their
ends come into the cave again."

"Right; go on."

"The fences are fastened to heavy oaken posts only
three feet apart, and these posts are sunk five feet in
the ground."

"That is good and strong."

"Yes. The wires have no ground-connection outside
of the cave. They go out from the positive brush
of the dynamo; there is a ground-connection through
the negative brush; the other ends of the wire return
to the cave, and each is grounded independently."

"Nono, that won't do!"

"Why?"

We have hundreds more books for your enjoyment. Read them all!

"It's too expensive -- uses up force for nothing.
You don't want any ground-connection except the one
through the negative brush. The other end of every
wire must be brought back into the cave and fastened
independently, and WITHOUT any ground-connection.
Now, then, observe the economy of it. A cavalry
charge hurls itself against the fence; you are using no
power, you are spending no money, for there is only
one ground-connection till those horses come against
the wire; the moment they touch it they form a connection
with the negative brush THROUGH THE GROUND,
and drop dead. Don't you see? -- you are using no
energy until it is needed; your lightning is there, and
ready, like the load in a gun; but it isn't costing you
a cent till you touch it off. Oh, yes, the single
ground-connection --"

"Of course! I don't know how I overlooked that.
It's not only cheaper, but it's more effectual than the
other way, for if wires break or get tangled, no harm
is done.

"No, especially if we have a tell-tale in the cave
and disconnect the broken wire. Well, go on. The
gatlings?"

"Yes -- that's arranged. In the center of the inner
circle, on a spacious platform six feet high, I've
grouped a battery of thirteen gatling guns, and provided
plenty of ammunition."

"That's it. They command every approach, and
when the Church's knights arrive, there's going to be
music. The brow of the precipice over the cave --"

"I've got a wire fence there, and a gatling. They
won't drop any rocks down on us."